Unidad folicular

From one to five capillary terminals.
A single hair (rarely two).
Up to nine sebaceous glands (producing a vital substance that conditions the hair and skin).
The arrector pili muscle (responsible for keeping the hair constantly upright).
The bulb (the living part of the hair where cells divide every 24–72 hours faster than in any other part of the body).
The papilla (base of the follicle containing a perifollicular vascular plexus and a perifollicular neural network).
And the perifollicle (a circumferential band of fine adventitial collagen that defines the unit).

The hairs are grouped into follicular units.

Humans have approximately 90,000 to 150,000 hairs on the scalp, a number that varies from person to person depending on density.